In a semiconductor manufacturing process, an electrostatic chuck is used for attracting and holding a semiconductor substrate in various apparatuses such as an ion implantation apparatus, an ion doping apparatus, a plasma immersion apparatus, an lithographic apparatus using, for example, an electron beam or extreme ultraviolet (EUV) lithography, and a wafer inspection apparatus for silicon wafers or the like. In addition, in the field of liquid crystal manufacturing, the electrostatic chuck is used for attracting and holding an insulating substrate in a substrate laminating apparatus, which is used for injecting liquid crystal between glass substrates, or in an ion doping apparatus.
The electrostatic chuck is generally formed by laminating, on an upper surface side of a metal base, an electrode sheet for attracting a substrate such as a semiconductor substrate or a glass substrate. Then, when a predetermined voltage is applied to an attraction electrode included in the electrode sheet, an electric charge and an electric field are formed on a surface of the electrode sheet, and with this surface serving as a substrate attracting surface, the substrates is attracted with electrical force. A dielectric material, a semiconductor, and a material containing a metal are applicable as the substrate to be attracted. However, as for attraction force to be generated, in a case in which the substrate to be attracted is a non-conductor such as glass or a polyimide resin, static electricity occurs, but almost no current flows in those materials. Thus, the attraction force relies on gradient force obtained through spatial derivative of the electric field. On the other hand, in the case of a semiconductor substrate such as a silicon wafer or a conductor such as a metal, the attraction is achieved by the Johnsen-Rahbek force, which has even higher attraction force. The attraction force varies depending on the type of a target substrate, the attraction mechanism by which the attraction force is generated, and such other factor. However, in general, the attraction force is said to range from several g/cm2 to several hundred g/cm2, which are relatively high values.
By the way, when the electrostatic chuck is used in such a substrate processing apparatus as a semiconductor manufacturing apparatus or a liquid crystal manufacturing apparatus, a high-voltage power supply is installed remotely outside the electrostatic chuck, and power is supplied to the attraction electrode from this external power supply via a wire, a connector, and the like, to thereby acquire a predetermined attraction force. Specifically, the electrostatic chuck side includes an input terminal for supplying power to the attraction electrode, and attracts/holds the substrate while receiving the supply of the power from the external power supply. For this reason, the physical range of use of the electrostatic chuck is affected to no small degree by the installed location of the external power supply. To address this, for example, there are proposed electrostatic chucks including a battery as the internal power supply (see Patent Literature 1 and Patent Literature 2). According to those electrostatic chucks, the main body of the electrostatic chuck includes a power supply, and hence, for example, during or after the processing of the substrate, it is possible to move/transport the substrate in a state in which the substrate is held.